Atezolizumab Trial in Endometrial Cancer - AtTEnd (AtTEnd Trial)

Atezolizumab is an engineered humanised monoclonal immunoglobulin G1 antibody that binds selectively to PD-L1 and prevents its interaction with PD-1 and B7-1. In May 2016 atezolizumab was approved by the FDA for patients with locally advanced or metastatic urothelial carcinoma who have disease progression during or following any platinum-containing chemotherapy, or within 12 months of receiving chemotherapy before surgery (neoadjuvant) or after surgery (adjuvant); in October 2016 it was approved by the FDA for patients with metastatic non-small cell lung cancer (NSCLC) who have disease progression during or following platinum-containing chemotherapy, and have progressed on an appropriate FDA-approved targeted therapy if their tumor has EGFR or ALK gene abnormalities. Finally, in April 2017 atezolizumab was granted accelerated approval by FDA for the first-line treatment of patients with locally advanced or metastatic urothelial carcinoma who are not eligible for cisplatin chemotherapy. Combinations of atezolizumab with chemotherapeutic agents and/or targeted therapies were studied in different solid tumors such as melanoma, NSCLC, renal cell carcinoma and colorectal carcinoma. From these studies the AE profile of atezolizumab combinations were consistent with that of the individual agents. Finally, preliminary results of a Phase Ia study of Atezolizumab (NCT01375842) monotherapy in relapsed endometrial cancer were reported as abstract at ASCO 2017. Fifteen patients were evaluated for safety and efficacy with a minimum follow-up of 11.2 months. No G4-5 related AEs occurred. Regarding efficacy ORR was 13% \[2/15\] by RECIST. Atezolizumab seemed to have a favorable safety profile, with durable clinical benefit in some patients. Further studies with atezolizumab are warranted given its promising results in advanced endometrial cancer and the limited efficacy of current treatment options.